Microsoft’s quantum computer could be the most dependable yet

Microsoft and quantum computing company Quantinuum claim to have developed a quantum computer with unprecedented levels of reliability. The ability to correct its own errors could be a step toward more practical quantum computers in the near future.

“What we did here gave me goosebumps. We showed that error correction is reproducible, works, and is reliable.” Krista Svoir At Microsoft.

Experts have long expected the arrival of practical quantum computers that can complete calculations too complex for traditional computers. Although quantum computers have steadily grown larger and more complex, this prediction has not yet been fully realized. One big reason for this is that all modern quantum computers are subject to errors, and researchers have found that it is technically difficult to implement algorithms to detect and correct errors during calculations. That's it.

The new experiment could be an important step toward overcoming this error problem. The researchers say that on his H2 quantum processor at Quantinuum, he ran more than 14,000 individual calculation routines without making a single error.

Errors occur even in classical computers, but error correction can be coded into programs by creating backup copies of the information being processed. This approach is not possible with quantum computing because quantum information cannot be copied. Instead, researchers distributed it across a group of connected qubits, or qubits, creating what are known as logical qubits. Microsoft and the Quantinuum team created four of these logical qubits using 30 qubits.

Svore said a process developed by Microsoft was used to generate these logical qubits, allowing them to run error-free, or fault-tolerant, experiments repeatedly. Typically, individual qubits are easily disturbed, but at the level of logical qubits, researchers were able to repeatedly detect and correct errors.

The approach was so successful, they say, that four logical qubits produced only 0.125 percent of the errors that would occur if 30 qubits were left ungrouped. This means that ungrouped qubits generate as many as 800 errors for every one error generated by a logical qubit.

“Having a logical error rate that is 800 times lower than that of physical qubits is a huge advance in the field and brings us one step closer to fault-tolerant quantum computing,” he said. says. mark suffman from the University of Wisconsin was not involved in the experiment.

jennifer strobley Quantinuum said the team's hardware is well-suited for new experiments because it provides advanced control over qubits and quantum computers have already achieved some of the lowest error rates ever. .

In 2023, a team of Harvard University researchers and their colleagues, including members of the quantum computing startup QuEra, broke the record for the largest number of logical qubits at once, 48. This is much more than his four logical qubits in the new device. But Strabley said the new device requires fewer physical qubits for each logical qubit, and the logical qubits have fewer errors than the one built by the Harvard team. “We used significantly fewer physical qubits and got better results,” she says.

However, some experts new scientist Without details about the experiment, researchers were not yet ready to qualify this new research as a breakthrough in quantum error correction.

It is generally believed that only quantum computers with more than 100 logical qubits can actually tackle scientifically and socially relevant problems in fields such as chemistry and materials science. The next challenge is to make everything bigger. Strabley and Svore say they are confident that the long-standing collaboration between Microsoft and Quantinuum will soon come to fruition.